Matière Interstellaire et Cosmologie

You are here

Interstellar Matter and Cosmology

Welcome to the pages of the team Matière Interstellaire et Cosmologie (MIC) !

The team is made of two groups, Matière interstellaire (Interstellar Matter) and Cosmologie (Cosmology). Our research activities span a broad range of fields, from the physics of interstellar dust grains to the cosmology of the primordial universe. Details can be found on the Presentation page and on the thematic pages.

The stratospheric balloon carrying the PILOT instrument was launched from Timmins in Canada at 9 pm (local time) on Sunday, September 20th. The gondola, weighting more than a ton, the heaviest the CNES took in the last 25 years, was lifted by a stratospheric balloon of 800.000 m3 and reached the altitude of 39.500 m after 3 hours of ascent. After a last transfer of helium carried out just before take-off, the detectors reached nominally their operating temperature of 320 mK when the balloon reached its flight ceiling, and the scientific observations could then start.

To reconcile the standard cosmological model with the X-ray measured number of galaxy clusters, a team of French scientists has shown that the cluster masses should be increased by 70% compared to current estimates. These results follow the conclusions obtained by the Planck mission in 2013 from observations of galaxy clusters in the microwave domain. This huge difference is intriguing: either our understanding of the physics of galaxy clusters needs to be revised, or the standard cosmological model is incomplete.

Many new and enigmatic high redshift galaxies that are intensively forming stars have been discovered using ESA’s Planck and Herschel satellites . These galaxies occur in clumps – and could be the long-sought formation phase of galaxy clusters. Some appear very bright, and have been found to be gravitationally lensed galaxies. These rapidly star-forming galaxies could help solve a central problem in cosmology: how did the large scale structure of galaxies form?

News about Dark Matter, neutrinos, first stars and the cosmological model: the Planck collaboration, with a leading participation of the Institut d'Astrophysique Spatiale, has just published nearly twenty articles revealing many important results that will allow to better understand major chapters in the book of the Universe.

By analysing their data jointly, the Planck and BICEP2/Keck collaborations have shown that the detection of primordial gravitational waves through the observation of the polarisation of the Cosmic Microwave Background (CMB) has not occurred yet. This result constitutes the denouement of the scientific drama that kept enthralled cosmologists and universe enthusiasts alike since March 2014: the signal, the detection of which has been reported by the BICEP2 team, is not related to the first instants of the Big Bang. It results from the combination of the Galactic signal and of gravitational distortions of the CMB during its propagation down to us.